Rattling the cage: Behaviour and resource use of mice in laboratory and pet cages

Conventional housing for laboratory mice limits the expression of species-specific behaviours and restricts the control over their environment, thus failing to guarantee the animals’ welfare. To better understand the behaviour and resource use of laboratory mice, we housed mice (n = 64) of two common laboratory strains (C57BL/6 and Swiss), both sexes and two group sizes (3 and 5) in large extensively enriched pet cages and conventional laboratory cages, respectively, and assessed their behaviour, resource use, and space use under these different housing conditions. Mice in pet cages showed more running, mostly on the running disc, and other locomotor behaviour, but also spent much time hidden in deep bedding, while mice in conventional laboratory cages climbed more on the cage grid, reared more and exhibited more stereotypic behaviour. Our findings emphasize the significance of a proper substrate for shelter, as well as other resources that facilitate species-specific behaviour.